# 31/32" drill size

A 31/32 in drill is 0.9688 in (24.61 mm). It sits between 61/64 in and 63/64 in in the fractional series; the nearest metric drill is 24.6 mm.

## 31/32" drill data

- Series: Fractional drill
- Decimal: 0.9688 in
- Metric: 24.61 mm (24.6062 mm exact)
- Nearest metric drill: 24.6 mm (−0.006 mm)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 24.6 mm | 0.9685 | −0.006 mm |
| 24.7 mm | 0.9724 | +0.094 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| Letter Z | Letter | 0.4130 | 10.49 |
| 61/64" | Fractional | 0.9531 | 24.21 |
| 31/32" | Fractional | 0.9688 | 24.61 |
| 63/64" | Fractional | 0.9844 | 25.00 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| M27 × 3 | 24 mm | 61 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| M22 bolt | 22 mm | 2.61 mm | 1.30 mm | Normal fit (normal 24, loose 26 mm) |
| M24 bolt | 24 mm | 0.61 mm | 0.30 mm | Tighter than close fit (25 mm) |


## FAQ

**What size is a 31/32 in drill?**
A 31/32 in drill is 0.9688 in, which is 24.61 mm (24.6062 mm exactly).

**What is the metric equivalent of a 31/32 in drill?**
The nearest metric drill is 24.6 mm, 0.006 mm smaller. The other close size is 24.7 mm.

**What thread can I tap with a 31/32 in drill?**
It leaves about 61 % thread in M27 × 3.

**What does a 31/32 in drill clear?**
It clears a M24 bolt with 0.61 mm total clearance (0.30 mm per side); for metric bolts: tighter than close fit.

Source page: https://machinistcharts.com/drill-size/31-32-inch/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)